TVCustomDrawItem (C++)

Description

The following example shows how the OnCustomDrawItem event handler draws items and lines of the tree view after the OnCustomDraw event handler has filled in the background.

Code

void __fastcall TCustomDrawForm::TVCustomDrawItem(TCustomTreeView *Sender,
          TTreeNode *Node, TCustomDrawState State, bool &DefaultDraw)
{
  TRect NodeRect;
/*
        If DefaultDraw is True, any of the node's font
    properties can be changed. Note also that, when 
    DefaultDraw = True, Windows draws the buttons and 
    ignores your font background colors, using instead 
        the TreeView's Color property.
*/
        if (State.Contains(cdsSelected))
        {
          TV->Canvas->Font->Assign(SelectedFontDialog->Font);
          TV->Canvas->Brush->Color = SelBkgColorDialog->Color;
        };
 
        DefaultDraw = FDefaultDrawItem;
/*
    DefaultDraw = False means you have to handle all the
    item drawing yourself, including the buttons, lines,
    images, and text.
*/
        if (!DefaultDraw)
        {
      //Draw the selection rectangle.
          if (State.Contains(cdsSelected))
          {
                NodeRect = Node->DisplayRect(True);
                TV->Canvas->FillRect(NodeRect);
          };
          NodeRect = Node->DisplayRect(False);
 
          if (None1->Checked)
      //No bitmap, so paint in the background color.
          {
                TV->Canvas->Brush->Color = BkgColorDialog->Color;
                TV->Canvas->Brush->Style = FBrushStyle;
                TV->Canvas->FillRect(NodeRect);
          }
          else
        //Do not paint over the background bitmap.
                TV->Canvas->Brush->Style = bsClear;
 
          NodeRect.Left = NodeRect.Left + (Node->Level * TV->Indent);
      // NodeRect.Left now represents the leftmost portion 
      // of the expand button.
          DrawButton(&NodeRect, Node); // See the CustomDraw demo.
 
          NodeRect.Left = NodeRect.Left + TV->Indent + FButtonSize;
          //NodeRect->Left is now the leftmost portion of the image.
          DrawImage(&NodeRect, Node->ImageIndex); // See the CustomDraw demo.
 
          NodeRect.Left = NodeRect.Left + ImageList->Width;
      //Now you are finally in a position to draw the text.
 
          TV->Canvas->TextOut(NodeRect.Left, NodeRect.Top, Node->Text);
        };
}

Uses

• Vcl.ComCtrls.TCustomTreeView.OnCustomDrawItem ( fr | de | ja )
• Vcl.ComCtrls.TTreeNode.DisplayRect ( fr | de | ja )
• Vcl.ComCtrls.TTreeNode.Level ( fr | de | ja )
• Vcl.ComCtrls.TCustomTreeView.Indent ( fr | de | ja )